You can add gadgets from Atlassian applications such as Confluence, JIRA and others. You can also add gadgets from other websites such as iGoogle. Many public gadgets will work on an Atlassian dashboard. Some gadgets may rely on specific iGoogle features that will not work properly on Atlassian dashboards. In that case, you can simply remove the gadget from the directory or you may not be allowed to add the gadget at all.